Typewriting machine



2, 1932 4 w. A. DoBsoN I 1,870,

'nrzwax'rmoncams -Filad llaron 11, 1929 '5 upper-case position.

Patented Aug, 2,, 1 932.

[UNITED STATES PATENT OFFHIE A. DOBSOILT, OF BRIDGEPORT, CONNECTICUT, ASSIGNOR TO UNDER'W'OOD EL- LIOTT FISHER COMPANY, OF NEW YORK, N. Y., A CORPORATION OF DELAWARE TYPEWRITING MACHINE Application filed March-11, 1929. Serial No. 345,954.

This invention relates generally to typewriting machines having shirt-frames and more particularly tomeans for guiding a typewriter shift-frame from lower-case to In a portable typewriting machine, to which the present invention may be advantageously applied, the platen-carrying shiftframe is usually guided from lower-case to upper-case position by means of a pair of links at each side of the shift-frame. Each pair includes an upper and a lower link, each aving its front end fastened to the shiftframe and its rear end fastened to the main frame of the machine. It is essential for securing good typing results that the plane of the printing line of the platen coincides with the plane of the work-faces of the types when-the latter are brought to the printing point.

It is a feature of the present invention to incorporate in each upper link light, compact means, which are operable to vary the position or the effective length of the link for moving the platen angularly, to brin the plane of the printing line into coinci ence with the plane of the types at the printing point, these means operating without causing the links to bind or be strained. In carrying out this feature of the invention, each upper link is built up of two parts or ele- Inents which overlap and are adapted for lengthwise adjustment by a small eccentric screw-device.

Other features and advantages will hereinafter appear.

In the accompanying drawing,

Figure 1 is a fragmentary sectional view, from front to rear, through an Underwood portable typewriting machine, having my invention applied thereto.

Figure 2 is a. fragmentary perspective view of the structure shown in Figure 1.

Figure 3 is a disassembled perspective view of an improved link employed in connecting the main frame to the shift-frame according to my invention.

The present invention is illustrated as applied to an Underwood portable typewritmg machine which is provided with a main frame The shift-frame 18 is mounted for up-anddown movement between side frame-members 20 of the main frame 10, on an upper and a 7 lower link or arm 21 and 22, respectively, at the left side of the shift-frame 18, and an upper and a lower link or arm 23 and 2 1, respectively, at the right side of the shiftframe 18. Since the upper link 21 is a duplicate of the other upper link 23, except that it is made for use at the left-hand side of the shift-frame, and the link 23 is made for use at the ri lit-hand side of the shift-frame, only the le t-hand link 21 will be described in detail. For a like reason only the left-hand lower link 22 will be described.

The upper link 21 includes a body or element 25 whose rear end has an aperture 26 for engaging around a usual shoulder-stud 27 which extends inwardly from the side framemember 20, to which it is fastened securely by a nut 28 set in a recess 29. The element 25 extends forwardly from the hole 26, and is curved to pass below the path of the carriage 1 1. The element 25 terminates at the front in a short straight forwardly-extending portion 30, and is bent outwardly at 31 from the plane of the curved portion.

The present invention provides compact, accessible, conveniently-operable means for varying the lengths of theaipper links 21 and 28 in a way that no flexing or warping strain on the links is caused. In carrying out this feature, the front portion 30 is made with a relatively large round hole 32 through it adjacent the bend 31, and has a lengthwise elongated slot 33 out through it in front of the hole 32.

The built-up link 21 also includes a for- (iii nated as 35, wh ch has a rear straight portion 36 of approximately the same width and length as the straight portion of the body 25 against which it is fastened facewise "by means to be presently described. There is provided in the rear portion 36, opposite the hole 82, a smaller plain hole 37, and, opposite the central portion of the slot 33, there is provided a small tapped hole 38.

The adjustable member has a downwardly-inclined front portion provided with a hole -11 adjacent its front end for engaging about. a usual pivot-member 12, which is fastened in the usual way in a front extension 43 of the shift-frame 18. A. collar 14: around the screw 12 spaces the member away from the extension 13.

It is a feature of the present invention to provide means for fastening the extensionmember 35 to the link-body 25 so that the length of the link 21 can be conveniently varied for adjusting the printing plane of, the platen. To this end, there is provided an eccentric screw-member having a threaded stem-portion 51, an integral cylindrical shoulder portion having a diameter for fitting tightly in the hole 32 and being cccentrically disposed relatively to the stem-portion 51, and a slotted head-portion larger in diameter than the hole When the axis of the fastening hole 411 is positioned the normal distance from the axis of the hole 26 called for by the design of the machine, the threaded stem-member 51 will preferably be disposed directly above or below the axis of the cylindrical portion 52, and will pass through the hole 37 in the extension A screw fitting snugly in the slot 33 has a head 56 considerably larger in diameter than the width of the slot 82-3. The screw is threaded to engage in the tapped hole 38. When the eccentric screw-member 50 is as sembled with the body 51 the threaded stemmemher will pass through the hole 37 and receive a nut 57, which, being screwed up tight on the stem 51, helps to hold the extension 35 tightly against the straight portion 30 in the link 21. It can be seen that when the screw and the nut 57 are screwed up tightly. the extcnsionanember 3.1" will be strongly and rigidly secured to the body 25.

The lower links 22 and i may each have a hodv portion 55 provided with a hub 56 for f ning the body on a rock-shaft 57, which ex -nds between the side tramzmembers E20 and is pirotally mounted on usual pivotscrews An inreaching pin 59 is fastened securely in the forward end of each hodv 55 and extends through bearing holes in, the ad t idc of the shitt-tranic 1% to project from the latter. no it is desired to type capital work-sheet, not shown,

ample. on a around the platen. either letters,

a y engage two usual shi t-lqe'vs (l0 zs'iav be de- M 7-. one of pressed. Each key 60 is mounted on a rearwardly-extending key-lever 61, which may be pivotally mounted in a usual way and have a rearwardly-extending arm 62 whose rear end portion engages under the adjacent pin 59. The depression of either key 60, acting through the pin 59, body 55 and the rockshaft 57, raises the shift-frame to upper-case position from its normal lower-case position. The latter position is determined by a forward extension 63 of each body 55 resting on a head 64 of a usual screw 65, which is threaded in an integral lug 66 of the adjacent side frame-Inember 20. The upper-case position of the shift-frame is determined by the extension 63 engagin a head 67 of a usual screw 68, which is threa ed in a lug 69 of the side frame-member 20.

Each extension 63 may be formed with an integral goose-neck portion 70 (Figure 1) and have a forwardly extending portion 71, which is arranged to abut against the screw-heads 6 1 and 67.

It can be readily seen from inspection of Figure 1 that in varying the effective length of the link 21, the fastening hole 11 is moved toward or away from the fastening hole 26. This arrangement increases the eiliciency, i. e., the working range or extent of sidewise operative movement of the eccentric stemanem her 51, thus permitting an eccentric screw of minimum. size to be employed, which is especially desirable in a portable typewriting machine where a greater degree of lightness and compactness is always desirable.

A typewriter mechanic or repairman may save time in adjusting the platen. 12 by taking suitable measurements and ascertaining how much one end of the platen needs to be moved forwardly or backwardly to bring the plane of the printing line of the platen into coincidence with the faces of the types 16 when the latter are brought to the printing point. Then, because of the above-described adjusting means for the links 21 and the mechanic can estimate fairly closely how much to turn the screwhead 53 to shift the end of the platen for bringing the latter substantially into correct position. The remaining adjustment required. can the eafter be more quickly made by trial in a usual way than it the entire adjustment was made by trial.

It will be noted (see Figure 2) that the screws 50 and which are required to be unloosened for adjusting the lengths of the links 21 and 23, are positioned so that they can be reached and operated above the rim of the main frame 20, by an ordinary short screwdriver in one hand of the mechanic, while the other hand holds a small wrench of any suitable kind in engagement with the nut or.

It will be seen that each guidelink is built up of two link-elements overlapping at their ends, the overlapping portions being rigidly' fastened facewise against each other by two screws, which are both accessible above the brim of the machine frame, making it unnecessary to alter the latter.

One screw has a large shoulder 52 that fits tightly and has a shank 51 upon the end of which is threaded fastening nut 57. This shoulder 52 is eccentric to shank 51, which is threaded into the other link-element 35. By turning this screw, which remains tight in the hole, there occurs a relative displacement of the two link-elements 21 and 35 forward or back, thereby altering the length of the link. It is only necessary to turn screw 53, thereby altering the length of the link, and then tighton the nut 57, to hold the links firmly together. Additional firmness may be provided for by the use of the second screw 56, which is also threaded into the short link-element 35. Both of the fastening screws are readily accessible by an ordinary screw-driver above the brim of the main frame 20, and room is not taken up in the machine that is needed for other mechanisms and connections.

Variations may be resorted to within the scope of the invention, and portions of the improvements may be used without others.

Having thus described my invention, 1 claim:

In a portable typewriting machine having a one-part carriage, tracks on which the carriage runs, a nontraveling frame on which said tracks and carriage are shiftable up and down, and a guiding device for the lower portion of said frame, means for guiding the upper portion of said frame, including two links at the sides of said frame, each guide-link having one link-element that is pivoted to the main frame of the typewriter, and another linleelement that is pivoted to said shiftable track-frame, and also including means adjustably securing said link-elements together in a manner to secure adjustability of the elements, for varying the length of the guidelink, said securing means includin a screw having a large shoulder fitting tig tly in ahole in a main link-element, said screw hav ing a threaded shank extending through the other link-element and provided with a fastening nut, said shoulder being eccentric to said shank, to effect relative adjustment of the link-elements, the shoulder of said screw remaining tightly fitted in said hole, and a second screw passing through one of said elements and threaded into the other thereof, for completing the fastening of the link-elements together, one of said link-elements being slotted to accommodate relative shifting of said elements effected by said shouldered screw.

WILLIAM A. DOBSOll.

in a round hole 32 in link-element 25, 

